Hearing devices generally have a housing, in which a microphone, an amplifier facility, a receiver and an energy supply facility are disposed. A receiver tube connects the receiver to the acoustic output or sound outlet of the housing, to conduct the acoustic signals generated by the receiver. In the case of a behind-the-ear (BTE) hearing device, the housing is connected by way of a connector piece to a carrier hook, which has a sound channel. The acoustic signal generated by the receiver is hereby transmitted to the ear by way of the receiver tube, the housing connector piece and the sound channel.
A hearing device is known from EP 1 443 802, with a tubular connector element to connect the output to a tube for sound transmission into the ear canal. The internal diameter of the acoustic transmission channel in the connector element corresponds roughly to the external diameter of the tube, so that the latter can be inserted into this acoustic transmission channel. The tube is guided into the connector element and disposed there in a secure manner, for example by bonding, welding, slip-resistant configuration of the boundary surface between the tube and connector element, etc.
It is known from the prior art that acoustic feedback can result if the securing system for the receiver tube is not sealed. Some of the acoustic signal generated by the receiver then escapes from the receiver tube by way of the unsealed securing system, passing into the interior of the housing. The acoustic signal is picked up there by way of the microphone and converted to an electrical signal. The weak electrical signal is then amplified in the amplifier facility and forwarded to the receiver. The receiver converts the electrical signal back to an acoustic signal. This produces acoustic feedback, which the hearing device wearer may perceive as an unpleasant whistle.
Elderly people frequently experience a deterioration in their perception of high frequencies, which makes it difficult to understand spoken speech. Therefore acoustic signals in the high-frequency range principally are processed and amplified by the hearing device. With the unsealed securing system described above therefore acoustic signals in the high-frequency range predominantly escape into the interior of the housing and cause acoustic feedback.
To prevent acoustic feedback, attempts have therefore been made to date to connect the receiver tube and housing connector piece to each other in the most airtight and/or acoustically sealed manner possible. This is intended to prevent the passage of sound and/or acoustic signals through the connection.
It has however proven that a receiver tube made of a rubber material and a connector piece made of metal or a metal alloy cannot be connected to each other in a sealed manner easily.
It is therefore generally known from the prior art that the receiver tube can be secured using an adhesive, for example Loctite, Crotoflex or Uhu Plus, to a corresponding receiver connector section and/or a housing connector piece, thereby sealing it.
However this has various disadvantages. For example an additional securing step using adhesive is required.
Also if the hearing device is dropped, the receiver tube can come loose or become detached from its securing system, which in turn results in a lack of seal for the securing system and the associated disadvantages of acoustic feedback.
A further disadvantage is that the manufacturing tolerances for the receiver tube and the corresponding connector piece are relatively small, to ensure an essentially sealed connection. Also when the receiver tube is secured with adhesive, it cannot easily be removed for cleaning purposes.
Also over time the adhesive becomes brittle and cracked and no longer provides a seal. A further disadvantage is that parts, such as the receiver and microphone for example, can be damaged by adhesive thinners.